Hot water supply system



Feb. 25, 1941.-

3 Sheets-Sheet 1 w. c. GROENIGER 2,233,050

HOT WATER SUPPLY SYSTEM Feb. 25, 1941.

Filed Nov. 10, 1937 s Shets-Sheet 2 I EH2.

Tia-3 A INVENTOR W. C. GROENIGER HOT WATER SUPPLY SYSTEM Feb. 25,1941.

3 Sheets-Sheet 3 File'gl Nov; l0, 1937 INVENTOVR Wll am CGroem er Y E NR O Patented Feb. 25, 194.1

PATENT OFFICE HoTWArEe SUPPLY SYSTEM William C. Groeniger,Columbus,[0hio, assignor toJohn" B. Pierce Foundation, New York, N; Y.,a. corporation of New York v Application Noveinber 1a, 1937, Serial'No.173,912. 4 Claims. ((1126-3632) This invention relates to improvementsin hot water supply systems, and particularly to systems supplying hotwater for domestic purposes,

This invention is applicable to various domestic hot water systems, and"is ;of particular value in systems embodying acontinuous circulation ofheated water from and to a storage tank through i a closed. circuit pipe.line, at required stations along .suchline, there. being risers and/or,branchessupplying taps or equivalentdraw-ofi devices. l Y 1. u

As is well known, flow of water is induced by thermo-syphonic effect,namely, resulting from the difference in weight of equal volumes ofwater at different temperatures. This invention provides novel means.for utilizing the thermosyphonic effect of temperature differentialsina I closed circuit, and attains advantages resulting from such novelmeans.

Pursuant to this invention, water is Withdrawn from the storage tankprimarilyfrom a zone arrangedbetween a zone of water at elevatedtemperature, located at an upwardly portion of the tank, and a .zone ofcomparatively cool-tempera ture, located at a lowerly portion-of thetank. As

water. is drawn from such intermediate zone, the heating effect of theWater of theupper zone commingles'to an extent with the water of thecentral, i. e., intermediate, Zone and thus counterbalances the coolingeffect caused by the com,-

' mingling of the Water of the lower zone. By, ar-

ranging- .a substantial reservoir of water in the upward zone, ofrelativelyhigh temperature, the eifective tank capacity may be reduced,for a given output of water at any desired elevated temperature, ascompared with systemsnot em ploying the invention. Pursuant to theinvention. additionally, a relatively great differenceinwatertemperature exists at the inlet and outlet connections at the tank, suchdifference having great effect in initiating thGIIHOrSYPhOHiCcirculation.

The invention directs infiowing ,cold waterto the tank, prior to itsflow to the water heating means, to effect a preheating of such .Water.Such F preheating is effected by abafile or other water diffusion meanswithin the tank, i. e., at the outlet of the cold water fitting, suchbaffle diverting the inflowing cold water stream into and along thelower portion of the. storage tank. The water thus is diffused andadmixed with arm water in such, lower tank portion before flow tothe hotwater heating device. The stated baille prevents di ect o of n m ng co dwater to the hot Water in the central, i. e., intermediatearld u perportions of the tank, and particularlyprevents a direct passage of suchcold Water to the hot water draw-off fitting. r

A further feature is that although water flowing through thereturn lineof the circulating system may passdirectly to. the hot water heater,only .a very small part. of the extremely hot water leaving the heateris permitted to flow into the line supplying the domestic plumbing orother fixturesat which hot: water is made available, such small flow ofvery hot. water serving toaccelerate ,thermo-syphonic ;circulationwithout raising the water temperature at the draw-off stations to adangerous or undesirable degree.

"Yet another feature of the invention is that during .a period ofinactivity of the hot water heater, such inactive period beingoccasioned by the function of conventional thermostatic. or other watertemperature control devices, reversed circulation "within the system iseffectively-pre eluded, Additionally, the invention precludes short.circuiting of the circulation system, i. e., a condition of flow inwhich cold water, flowing into the system to replace hot water beingdrawn off .short circuits to the point of hot Water withe drawal. f Y

,The invention further provides for substantial simplification of pipingat the hot water storage tank or equivalent, actualconnection therewithbeing limited to unitary fittings to which all incidental pipingconnections are made. 30

Other features and advantages will hereinafter pp ar it i In theaccompanyin drawi r Fig. .1 represents a hot water supply circulatingsystem installed pursuant to this invention, and employing ,a form ofcirculation device set forth herein 113.5368 2, hot waterstorage tank orreservoir forming part of my improved hot water supply circulatingsystem. The tank I!) ispreferably enclosed in a boiler covering orlagging II of asbestos or similar material for the purpose of conservingthe heat of the stored water. Where the tank or reservoir in is ofrelativelylarge size .55

it is preferably mounted horizontally on suitable supports.

mote from the cold water fitting I3, a second tapping, as I4, permits ahot water fitting," i. e., tank inlet and distribution fitting I5, to'besimilarly connected to the tank.

A heater I3, the rate offuel combustion in which may be controlled'byconventional thermostat, heats water for storage in tank I9, cold waterline H connecting into fitting I3, and hot water line I8 from the heaterconnecting into fitting I5.

7 Referring now to Figs. 2 and 3 where the cold water fitting I3 isshown in detail, the hollow body of the fitting I3 has a suitabletubular extension I9 connecting therewith, one element of the extensionpreferably being a polygonal shoulder 20 engageable by a wrench orequivalent tool. Additionally, extension I9 may be threaded at 2| forcooperation with tapping I2; fitting I3 thus may be screwed into andthrough the wall of the tank III, as shown in Fig. 4. Extension I9, seeFig. 3, terminates in a sediment collar or rim 22 of suitable diameter.The length of rim 22 serves to position the open end thereof above thebottom of tank I0, and therefore above an accumulation of sediment.

The body of the cold water fitting I3 at the point remote from theextension I9 is drilled and tapped as indicated to receive a threadedhub 2301* a cold water inlet tube 24, the threaded hub being inpreferably water-tight association with the body of fitting I 3. Slots25 provide for the application of a key or similar tool with which thetube 24 may be screwed into proper position, in which, as shown in Fig.3, its end extends substantially above sediment rim 22. The terminal endrof tube 24 is provided with a plurality of outlets 26, positionedbeneath a suitably configurated closure which forms a deflecting plateor bafiie 21 for effecting a spread or diffusion of water preferablylongitudinally along the bottom portion of tank III, as later described.

Water tube 24 being concentric with extension I9, and as shown in Figs.2 and 4 passing through the latter in spaced relationship therewith, an

annular passage 28 is formed, providing for flow of water from tank II]into the body of the fitting I3. The body portion of fitting I3 ispreferably substantially spherical, thus providing for flow of wateraround the tube 24.

The body of cold water fitting l3 adjacent the threaded portion at 23may be provided with a flange 29 for cooperation with a companion flange29a having internal threads 30 for connection with a water supply main.Cold water tube 24 thus efiects a continuation of the water supply main,and except as later described, substantially all of the inflowing coldwater flows into tank III, subseouently entering the body of fitting I3through the annular passage 28 for flow through pipe H to heater I6. Inaccordance with conventional practice the stated flanges may be held inoperative and watertight association with eac other by the bolts 3| andnuts 32.

Cold water fitting I3 is further provided with a communicating passage34 extending perpendicularly to the axis of the cold water tube 24. Aflanged end 35 of passage 34 cooperates with a flange 36 arranged toreceive the threaded end 5 of pipe II, which leads to the heater Iii.Flanges 35 and 36 are maintained in cooperative water-tight relation bymeans of the bolts 38 and nuts 39. Preferably diametrically opposite thepassage 34, the cold water fitting I3 is 10 provided with afemale-threaded boss 40 form ing the point of connection with the returnline of the water circulation system, as later described.

Hot water supply fitting I5 may be structurally 15 similar to the coldwater supply fitting I3 except that, as shown in Fig. 4, the sedimentcollar may be eliminated from the tubular extension I9. As a counterpartof tube 24, fitting I5 is provided with a hot water tube 43, such tubebeing screw- 20 threadedly secured within thebody of fitting I5. Asclearly indicated in Fig. l, tube 43 passes through extension I9 andprojects downwardly into the-tank. A similar annular passage 23 is thusprovided in fitting I5. 25

Fitting I5 may have connected thereto a pipe 44 serving a temperature orpressure relief valve (not shown). By suitable flanged connections, apipe I8 leading from heater I6, and a pipe 45 for conveying hot water tovarious fixtures or other draw-off points may be connected to fittingI5.

Referring now to Fig. 1, the hot water circulating system includes amain 45, which as shown may be graduated size, such main supplyingsuitable taps 46 serving suitable plumbing fixtures in accordance withconventional practice. A return line 41 completes the circuit, saidreturn line connecting into the cold water fitting I3 at boss 49; thusprovision is made for a complete 40 circuit of water from and to thetank II). A conventional drain cock 48 may be provided, in accordancewith standard practice, to drain the tank and associated piping.Similarly, a drain (not shown) may be provided at heater IE to 45provide for the drainage thereof. A suitable piping connection, as 42,is made with a cold Water feed main.

The system is initially filled by flow of water from pipe 42, throughthe hollow tube 24 in fitting I3, thence into tank I9 and through tube43 to fill the hot water feed line 45 and return 41. As will be obvious,cold water line H, heater I6, and hot water line I8 will besimultaneously filled. 55

As indicated in Figs. 2 and l, the annular passages 28 provide channelsof water flow between the tank III and therespective body portions offittings I3 and I 5.

To rid the system of air, and thus prevent air 50 binding of tank IIIand the upper portion of pipe I8, there is provided a suitable openingor openings 59 in the side wall of tube 43; such opening or openings 50provide for the escape of air into main 45, from which it may beeliminated from the system through taps 46.

During the stage of heating of the water in tank II], a thermo-syphonicflow through pipe I8, downwardly throughannular opening 28 of fittingI5, through tank I0, then downwardly through 7 annular opening 28 offitting I3, and thence to the heater I6 through pipe I1 is set inmotion.Such circulation continues until an. actuating member 52 of thethermostat, see Fig. 4, has attained the setting point temperature ofthe 15 for entry into the tank thermostat. By operation of thethermostat, the combustion of fuel in heater It, may then besubstantially shut off, as in the circumstance of the use of oil or gasas fuel, or the combustion of a coal fire appreciably lessened throughsuitable automatic operation of damper means. Such fuel combustiondevices, being familiar in the art and not a part of this invention, arenot shown.

Air liberated from the Water in the system during the heating stagefinds its way through opening or openings 50 and thence into the piping45. Similarly, steam or other vapor generated during theheatingstagepasses into piping 45, where it is condensed by its contact withthe relatively cooler water therein. Dangerous accumulations and/ordischarges of steam'at the taps 46, are therefore precluded.

In substantial coincidence with the initial flow of heated water throughpipe l8 into the tank, thermo-syphonic. circulation through mains 45 andreturn line 41 is started. Such circulation is initiated by reason ofthe heating up of tube 43 and its water content byzcontact of the heatedwater flowing through fitting l and passing downwardly about the outersurface of tube 43 before passing through opening 28 into tank H]. Asubstantial difference in temperature is thus quickly created betweentube 43, and the water in main 45, return line 41 and cold water tube24. Circulation is accelerated by the direct entry of a relatively smallvolume of water at elevated temperature directly into tube 43, andthence into pipe 45, through openings 55a; it is additionally furtheredby the pumping effect of air and/or steam bubbles escaping throughopening 5il and flowing upwardly through piping 45.

If, during this stage of thermo-syphonic circulation through piping 45and 41, the heater It remains in full operative status, the heater willdraw the water through fitting I3, around tube 24 and into pipe l1,through which itwill pass through heater l5, pipe l8, and into fitting[5 ill. Such action accelerates the heating up of the water throughoutthe entire circulation system, as the comparatively cool water in thelower portion of main 4,5 and return line 41 is rapidly moved into heatabsorbing contact with heater I6. The accentuated circulation throughmains- 45 and return line 4'! accelerates the thermo-syphonic flowthrough the circulation system.

Should fuel combustion in heater I6 be shut off or restricted after thethermo-syphonic circulation through piping 45 and 41 has comand throughthe body of fitting l3, out annular opening 28 of such fitting and intothe storage tank, whence it will again enter pipe 45 via tube 43. Acontinual circulation thus exists regardless of whether the heater I6 isin operative or dormant status; the paths of circulation being in allcircumstances entirely nonconflicting and non-short-circuiting.

The drawing of water from the system. by the opening of any or all ofthe taps 46 does not interrupt the cycle of circulation; it acceleratesthe movement of water by drawing the hot water in the storage tank tothe highest elevation of the circulating system. Water drawn from thesystem will be simultaneously replaced by a flow of cold water throughconnection 42 entering the tank In through the openings 26 of tube 24,the bafile 2'! of suchtube deflecting the cold water along the bottom ofthe tank l0, and commingling it with the warm water already present inthe tank. It will be seen therefore that a direct flow of cold waterfrom fitting l3 to the top of tank I!) or to tube 43 of fitting I5 iseffectively prevented; such flow, if permitted would result in. adelivery of tepid water to the pipe 45, and would slow thermo-syphoniccirculation through the system. Preferably, the thermostat 52 is locatedadjacent the intermediate zone of the tank ID, to preclude rapidlowering of temperature, during the stage of hot water withdrawal,thereby conserving fuel in the operation of the heater 16. Assumingheater IE to be in dormant status when the flow of cold water into thetank commences, a considerable volumeof water must be drawn off at thetaps 46 before the water of the intermediate zone, in contact with thethermostat, is lowered in temperature, to initiate the operation of theheater. Accordingly, therefore the heater I6 is not subject tointermittent or spas modic' conditions of activity and inactivity. Whenthe heater l6 again becomes active, the

water flowing through I! will include relatively warm water from tank H)which flows downwardly through annular opening 28'of fitting l3, admixedwith warm water from return main 41, flowing around the tube 24 andthence into piping H. Excepting during the stage of initial filling,cold water does not come into contact with heater l6.

As indicated in Fig. 2, the cold water tube 24 are thermostaticallycontrolled and therefore intermittently heated, reverse flow is common,because when the hot water heater is inactive,

its large exposed surface causes it to function;

as a cooling element, the effect of which is to draw water downwardlythrough thenormal hot water pipe leading to the storage tank. In thisinvention, reverse flow is effectively checked because the method ofconnecting the hot water;

circulating return and the cold water supply through the cold waterfitting l3 utilizes the chilling effect of the water contained withincentral tube 24 tocool the water within the body of fitting I3;therefore the relatively heavier water;:

in this part of the system moves toward the lowest part of the system,namely the heater, Is.

As indicated in Fig. 4, thehot water supply tube 43 extends into thetank It to a point considerably below the upper surface of the tank;Preferably, the tube should project, say, onethird into the tank, theactual degree of projection being proportioned to the size of the tank.Such projection permits the accumulation of a. stratum of water oftemperature appreciably higher than required at taps 46 between theterminal opening 43a of the tube and the upper wall of the tank. Suchstratum or zone is indicated by the broken line AA in Fig. 4.

The diffusing effect of baffle 21' of cold water tube 24 similarlycreates a zone of cool water at the lower portion of the tank. Theapproximate location of such zone is indicated by the line BB.Intermediate the two zones, therefore, is a zone constituting the mainreservoir .40 In conventional water heating systems which of the tank,from which zone water flows upwardly through tube 43 in the normalcirculating cycle, and in the circumstance of a draw oii of water fromone of the taps 46. The sensitive element 52 of the thermostat isadvantageously located in such intermediate, 1. e., central, zone. Thereis therefore permitted a safe accumulation or storage of water, thetemperatureof which may be considerably above the desired temperaturefor domestic purposes. As Water is drawn from the intermediate zone, theresultant disturbance of water'within the tank will cause the hotterwater and water from the cooler zone to commingle with the water beingdrawn from the intermediate zone. Thus, the cooling effect of such lowerzone water is offset by an equivalent heating effect of water drawn fromthe upper zone. As water is never drawn directly from the upper zoneinto the circulating system, the higher average temperature within thetank may be maintained, and therefore a smaller capacity of tank, ascompared with other water supply systems not employing this invention,may be utilized. Also, as water in substantial volume may never flowdirectly from heater It to main 45 maximum effect of the stated heatermay be realized, by permitting the heatingof the water therein to adegree which in systems not using this invention would be dangerous.

The creation of a zone of hot water has the effect of forcing the waterthen in the tank downwardy therein, and thus enforces flow throughannular opening 28 in fitting l3 and into pipe I! communicating with thehot water heater It.

From the above, it appears that my invention 1 provides a circulatoryhot water supply system comprising a tank, a heating coil, a circuit oftap-provided, i. e. faucet-provided piping including a terminal pipecommunicating with an upper zone, preferably the upper central zone, ofthe tank for withdrawing hot water therefrom, such circuit of pipingfurther including a terminal pipe communicating jointly with a lowerzone of the tank and with one end of the heating coil, the other end ofthe heating coil being connected to an upper zone of the tank, andpreferably traversing the terminal pipe delivering hot water from thetank into the circuit of piping.

Whereas I have described my invention by reference to specific formsthereof, it will be understood that many changes and modifications maybe made without departing from the spirit of the invention.

I claim:

1. A circulatory hot water supply system comprising a tank, a heatingcoil, a circuit of faucetprovided piping including a terminal pipecommunicating with an upper zone of the tank for withdrawing hot waterfrom' the tank and further including terminal piping communicating witha lower zone of the tank to return warm water to the tank during theperiod of inactivity of the heating coil and warm water to one end ofthe heating coil during the period of activity of the heating coil,piping leading from a cold water supply traversing said warm waterreturn terminal piping and discharging into said lower zone of the tank,and piping connecting the other end of the heating coil to an upper zoneof the tank.

2. A circulatory hot water supply system comprising a tank, a heatingcoil, a circuit of faucetprovided piping including a terminal pipecommunicating with an upper central zone of the tank for withdrawing hotwater from the tank and further including terminal piping communicatingwith a lower zone of the tank to return warm water to the tank duringthe period of inactivity of the heating coil and warm water to one endof the heating coil during the period of activity of the heating coil,piping leading from a cold water supply traversing said warm waterreturn terminal pipe and discharging into said lower zone of the tank,and piping connecting the other end of the heating coil to an upper zoneof the tank, said last-named piping traversing said first-named terminalpipe delivering heated water from the upper central zone of the tankinto said circuit of piping.

3. A circulatory hot Water supply system comprising a tank, a heatingcoil, a circuit of faucet-provided piping including a terminal pipecommunicating with an upper zone of the tank for withdrawing hot waterfrom the tank and further including terminal piping communicating with alower zone of the tank during the period of inactivity of the heatingcoil to return warm water to the tank and warm water to one end of theheating coil during the period of activity of the heating coil, pipingleading from a cold water supply and extending through said warm waterreturn terminal piping thereby preheating said water supply anddischarging the same directly into the lower zone of the tank, pipingconnecting the other end of the heating coil to an upper zone of thetank, and thermostatic means responsive to the temperature of the waterin said upper zone of the tank for controlling the periods of activityand inactivity of the heating coil.

4. A circulatory hot water supply system com- N prising a tank, aheating coil, a circuit of faucetprovided piping including a terminalpipe communicating with an upper central zone of the tank forwithdrawing hot water from the tank and further including terminalpiping communieating with a lower zone of the tank during the period ofinactivity of the heating coil to return warm Water to the tank and warmwater to one end of the heating coil during the period of activity ofthe heating coil, piping leading from a cold water supply and extendingthrough said warm water return terminal piping thereby preheating saidwater supply and discharging the same directly into the lower zone ofthe tank,

piping connecting the other end of the heating coil to an upper zone ofthe tank, said lastnamed piping traversing said first-named terminalpipe delivering heated Water from the upper central zone of the tankinto said circuit of piping, and thermostatic means responsive to thetemperature of the Water in said upper central zone of the tank forcontrolling the periods ofactivity and inactivity of the heating coil.

WILLIAM C. GROENIGER.

